Printing device and printing system to manage print jobs based on print history and computer readable storage medium for storing a computer program therefor

Abstract

A printing apparatus connectable with an external storage device is provided. The printing apparatus includes a printer unit to execute a printing operation to print an image in a current print job, a print log provider to provide a print log, which indicates a record of the printing operation for the current print job, to the external storage device, a print log obtainer to obtain a preceding print log, indicating a record of an earlier printing operation executed earlier in the printing apparatus, provided to and stored in the external storage device, a print log examiner to examine the preceding print log and determine normality of the preceding print log based on the record of the earlier print operation, and a controller to permit the printer unit to print the image and restrict the printer unit from printing the image depending on normality of the obtained print logs.

1. A printing apparatus, which is connectable with an external storage device, comprising:
 a printer unit configured to execute a printing operation to print an image according to a current print job; 
 a print log provider configured to provide a print log, which indicates a record of the printing operation for the current print job, to the external storage device to be stored when the printer unit activates the printing operation; 
 a print log obtainer configured to obtain a preceding print log, indicating a record of an earlier printing operation executed earlier in the printing apparatus, wherein the preceding print log has been provided to the external storage device by the print log provider, and stored in the external storage device; 
 a print log examiner configured to examine the preceding print log and determine normality of the preceding print log based on the record of the earlier print operation indicated by the preceding print log; and 
 a controller configured to permit the printer unit to print the image when the print log examiner determines that the preceding print log is normal, and restrict the printer unit from printing the image when the print log examiner determines that the preceding print log is abnormal, 
 wherein the print log obtainer obtains the preceding print log including the identifier of the client among a plurality of print logs provided to the external storage device earlier and stored in the external storage device. 
 
     
     
       2. The printing apparatus according to  claim 1 ,
 wherein the print log provider provides the print log including the record of the printing operation and an identifier of a client that instructs the printing apparatus to print the image according to the current print job, to the external storage device. 
 
     
     
       3. The printing apparatus according to  claim 2 ,
 wherein the print log obtainer obtains a predetermined number of preceding print logs including a latest print log, the latest print log having been provided to the external storage device by the print log provider in the latest print job prior to the current print job. 
 
     
     
       4. The printing apparatus according to  claim 1 ,
 wherein the print log provider provides the print log to the external storage device to be stored therein after the printer unit activates the printing operation and, when the printing operation completes normally, updates the print log stored in the external storage device so that the updated print log indicates normal completion of the printing operation; and 
 wherein, when the print log examiner examines the preceding print log and determines that the preceding print log does not indicate normal completion of a preceding printing operation, the print log examiner determines that the preceding print log is abnormal. 
 
     
     
       5. The printing apparatus according to  claim 1 ,
 wherein the print log examiner examines the preceding print log and determines that the preceding print log is abnormal when the preceding print log is not written in a predetermined format. 
 
     
     
       6. The printing apparatus according to  claim 1 , further comprising:
 a subject determiner configured to determine as to whether the client that instructs the printing apparatus to print the image according to the current print job is a subject-to-examination client; 
 wherein, when the subject determiner determines that the client is a subject-to-examination client, the printer unit executes the printing operation after the print log obtainer obtains the preceding print log, and the print log examiner determines normality of the obtained preceding print log; and 
 wherein, when the subject determiner determines that the client is not a subject-to-examination client, the printer unit executes the printing operation, and activation of the print log obtainer and the print log examiner is omitted. 
 
     
     
       7. The printing apparatus according to  claim 2 , further comprising:
 a scanner unit configured to scan an original image and generate a print job to print the scanned image; and 
 an input unit to input the identifier of the client who instructs the printing apparatus to print the scanned image according to the print job. 
 
     
     
       8. A printing system, comprising a printing apparatus and an external storage device connected to the printing apparatus;
 wherein the printing apparatus includes: 
 a printer unit configured to execute a printing operation to print an image in a current print job; 
 a print log provider configured to provide a print log, which indicates a record of the printing operation for the current print job, to the external storage device when the printer unit activates the printing operation; 
 a print log obtainer configured to obtain a preceding print log, indicating a record of an earlier printing operation executed earlier in the printing apparatus, wherein the preceding print log has been provided to the external storage device by the print log provider, and stored in the external storage device; 
 a print log examiner configured to examine the preceding print log and determine normality of the preceding print log based on the record of the earlier print operation indicated by the preceding print log; and 
 a controller configured to permit the printer unit to print the image when the print log examiner determines that the preceding print log is normal, and restrict the printer unit from printing the image when the print log examiner determines that the preceding print log is abnormal, 
 wherein the print log obtainer obtains the preceding print log including the identifier of the client among a plurality of print logs provided to the external storage device earlier and stored in the external storage device. 
 
     
     
       9. A non-transitory computer usable medium to store computer readable instructions, which manipulate a printing apparatus having a printer unit and being connected to an external storage device to execute steps of:
 activating a printing operation to print an image in a current print job; 
 providing a print log, which indicates a record of the printing operation for the current print job, to the external storage device when the printing operation is activated; 
 obtaining a preceding print log, which indicates a record of an earlier printing operation executed earlier in the printing apparatus, wherein the preceding print log has been provided to the external storage device in the step of providing, and stored in the external storage device; 
 examining the preceding print log to determine normality of the preceding print log based on the record of the earlier print operation indicated by the preceding print log; 
 permitting the printer unit to print the image when the preceding print log is determined to be normal and restricting the printer unit from printing the image when the preceding print log is determined to be abnormal, 
 wherein, in the step of obtaining, the preceding print log including the identifier of the client among a plurality of print logs provided to the external storage device earlier and stored in the external storage device is obtained.